1. Field of the Invention
This invention generally relates to a semiconductor device, and more particularly, to a resistance random access memory (“RRAM”) device and method for fabricating the same.
2. Background of the Invention
RRAM is a memory device using materials with variable electrical resistance characteristics in accordance with external influences. Since the resistance will not change even after the power source has been disconnected, RRAM is a non-volatile memory device.
As other memory devices, RRAM includes a number of memory cells, each coupled to a word line and a bit line. A RRAM cell may include a bottom electrode for bit line connection, a top electrode for word line connection, and a resistive film as a variable resistor between the bottom and top electrode. The resistive film may be programmed to have high resistance or low resistance in two-state memory circuits to store one bit of data per cell, or a number of resistance-determined states in multi-state memory circuits to store multiple bits of data in a single cell. In order to have multiple resistance-determined states, the resistive film may need to provide high resistance value so that the memory may have more operation window to perform multi-bit memory operations.